


Caught Red-Handed

by mickie



Category: Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Canon-Typical Behavior, Canon-Typical Violence, Case Fic, Jim is a good boyfriend, M/M, Mycroft has a sweet tooth, Sherlock Being Sherlock, mercury poisoning
Language: English
Status: Completed
Published: 2019-08-01
Updated: 2019-08-01
Packaged: 2020-07-28 11:15:26
Rating: Not Rated
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 2,004
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20063113
Author URL: https://archiveofourown.org/users/mickie/pseuds/mickie
Summary: Sherlock is working on a case when John comes home with a new girlfriend and Jim tries to be helpful.





	Caught Red-Handed

**Author's Note:**

  * For [fabricdragon](https://archiveofourown.org/users/fabricdragon/gifts).

> This is my July entry for the Sherlock Challenge on Tumblr. The prompt is **caught red-handed**. Fabricdragon gave me the additional prompts of cookie(s) and my dear friend Carrie (get an AO3 account woman!) gave me the prompt of lock.
> 
> I tried to portray the chaos of Sherlock solving a case with too many things going on and everything happening at once but Sherlock still manages. Enjoy! (Because I was a bit rushed in finishing, apologies for any typos; they'll be fixed eventually.)

**Caught Red-Handed**

Sherlock looked up when he heard steps coming up the staircase. _Steps_. John and someone else. His date. It was a much softer footfall than John’s. Rolling his eyes, Sherlock sipped his tea and resumed looking through his microscope. Tissue and blood samples were certainly more interesting than John’s latest soon-to-fail relationship.

“Hello, Sherlock!” John said exuberantly as he opened the door to their flat. Slightly buzzed. Already in love. Fish and chips for dinner. Chocolate cheesecake for dessert. A petite strawberry blonde followed him. Nursing assistant. First job. Impressed by John’s degree and military accomplishments. Smarter than most of the others. Also quite buzzed.

Sherlock frowned and hoped they wouldn’t be too loud. “This is my flatmate, _the_ Sherlock Holmes!” John said cheerfully.

“What do you know about mercury poisoning John,” Sherlock asked as though John had said nothing. “At the molecular, cellular, tissue, and organ levels? Toxicologically speaking.”

John’s face fell but then he continued as though _he_ had not heard Sherlock’s words. “This is Sandra O’Carroll. She’s new at our clinic, transferred from the King’s College Centre.” 

Sandra smiled and giggled. “Pleasure to meet you Mr. Holmes. John’s told me all about you.” Sherlock smiled wanly. “We pretty much only talked about you and your cases tonight but we did have a grand time.”

“Yes, yes, fish and chips and then drinks at The Old Tram Tavern. Spectacular,” Sherlock said. “Try not to be too loud later tonight. I’m working. If you distract me, I’ll call my boyfriend and we’ll keep _you_ up.”

“Sherlock,” John grumbled. “Ignore him when he gets like that.” 

“Well, if he calls his boyfriend we could have a foursome,” Sarah suggested, causing John to blush.

Sherlock arched an eyebrow and then returned to his microscope. “Mercury poisoning, John.” 

John seemed a bit overwhelmed. “Hold on. Let me show Sandra the new blog I’ve written up about our latest case. She agreed to proofread it for me.”

“John,” Sherlock interjected. “What forms of mercury do you have at the hospital? I may need to do some testing.”

John paused and stared at Sherlock as he processed the question. “What?” he asked, shaking his head.

“Mercury, do you have any at the hospital?” Sherlock repeated.

“No!” John answered. “Well, hold on. Let me get Sandra set up so she can look at what I wrote. The research people probably have some.”

“This is work,” Sherlock sighed but then looked up when both John and Sandra gasped.

“What the bloody hell?!” John nearly yelled and then Sandra burst out laughing. He looked at Sherlock with a completely bewildered expression. “What the bloody hell, Sherlock? What is this?”

“Big and natural girls, huh, John,” Sandra said in between giggles. “And look at that one: big gonzo.”

“Sherlock! What did you do?!”

“John, I’m busy examining liver cell samples,” Sherlock noted. “Can you hurry up?”

“Wow! Sex doll fetish shop!” Sandra continued. “I would never have guessed. You don’t look like the type.”

“I’m not!” John said forcefully. “I don’t know what all this nonsense is about.”

Sherlock sighed again. John was obviously going to be of no help until the situation was sorted. “Just calm down for a minute. What are you looking at? Email? Google? Tabs?”

“They’re ads,” John said with a lot of frustration. He changed browsers. “And there’s that sort of thing in my email as well.”

“Naturally.” Sherlock took a sip of his tea and noted that it was cold. He rose to reheat it. “Just get Sandra set up. She doesn’t seem to mind the ads. I’ll figure it out in a minute.”

“I know this is somehow your fault,” John grumbled. “But to answer your questions, the symptoms of mercury poisoning are significant emotional changes, insomnia, headaches, neurological changes such as abnormal sensations, muscle twitching, tremors, weakness,  
muscle atrophy, and decreased cognitive function.”

“Interesting.”

“What’s this new case then?”

“It’s for Mycroft,” Sherlock explained. “Why don’t you go see if Mrs. Hudson baked white chocolate macadamia nut cookies that she said she would for Jim.”

John frowned. “I’m not fond of your boyfriend.”

“But she is and we get more baked goodies for it so run along and see if she’s got some,” Sherlock said. “I’ll figure out your computer.”

“These ads are kinda fun. I mean look, Mr. Gonzo’s Channel!” Sandra said. “Your case sounds interesting as well. Mercury poisoning?”

“Yes.”

“Sandra, why don’t you come with me and I’ll introduce you to Mrs. Hudson,” John said. “She’s our landlady and occasionally makes treats.”

“Sounds good.” The two of them waved to Sherlock and went downstairs. Sherlock texted Jim.

What did you do to John’s computer? -SH

Jim replied almost instantaneously.

Nooooooooothing! :D -JM

Unlikely. Did you download anything? -SH

No. -JM

Sherlock smiled. That answer told him what he needed to know to remove the ads from John’s computer. Although Sandra hadn’t seemed offended and it might raise John’s chances of success with her.

Did you know that Mycroft has a dozen boxes of Bourbons in his filing cabinet? -JM

_That text_ worried Sherlock. Jim liked causing trouble with Mycroft and his brother was bound to retaliate at some point. It had taken months for Jim to recover from Mycroft’s overreactions during the so-called interrogation and Sherlock still hadn’t quite forgiven his brother even though they were back to speaking to each other and Sherlock was working a few cases for Mycroft again.

Sherlock contemplated how to reply in a way that wouldn’t encourage Jim to further mischief.

Don’t get caught there. -SH

Pffffffft, darling, I have plenty of time. -JM

The Iceman is working on the Shelby case and *that* will take him days. -JM

Do I need to know about this? -SH

Nope. -JM

Just don’t touch it if he tries to pawn it off on you. -xoxoJM

Shaking his head, Sherlock walked over to John’s computer and sat down. Jim had clearly used John’s computer to visit those sights in order to achieve this result. He deleted the history and all the cookies and then rebooted the computer before going back to taking notes on the tissue samples.

“Oh, my god! Your boyfriend is so lucky!” Sandra exclaimed as she and John returned. “These cookies are delicious!”

John rolled his eyes. “Did you fix it?”

Sherlock didn’t look up. “Yes, obviously,” he mumbled absentmindedly. There was no need to blame Jim. “It was some sort of server issue. Nothing to do with your computer. A simple reboot did the trick. You shouldn’t see any of those ads anymore.”

“That’s a shame,” Sandra mumbled around a mouthful of cookie. 

John seemed unsure what to say but then showed her the blog and set her to proofreading. “What’s the case?” he asked. “Is it any good? Mercury poisoning?”

“Looks like it,” Sherlock replied. “It’s one of Mycroft’s but it’s actually interesting. And he asked as a personal favor.”

“Then your boyfriend _is_ involved.”

“I don’t think so,” Sherlock said, while rising and walking to the kitchen. “I’ll get more tea started and then maybe you can look at everything medically to see if I’ve missed something.” He filled the kettle and set it to boil. “We’re probably out of milk.”

“Had to start new cultures?” John asked and chuckled with resignation. Sherlock nodded. “Yeah, I’ve gotten used to tea without, _now_, thanks to you.” 

Sherlock smiled. “Take a look at what I’ve got while we’re waiting for the water.” John walked over to the microscope, sat down, and read Sherlock’s notes. “Victim travelled to Southeast Asia and then fell sick shortly after her return. NHS and private physicians couldn’t find a cause or make a diagnosis. Eventually they said it was an unclassified disease they couple must have picked up while travelling.”

“Could be.”

“Her travelling companion also fell ill but recovered. Her family doesn’t know what to think but isn’t convinced.”

“She has all the hallmarks of mercury poisoning,” John said. 

The kettle whistled and Sherlock poured it into the teapot before returning to the table. “Seems pretty straightforward.”

“Except it’s not if you’re working the case and Mycroft is somehow involved,” John said. Sherlock nodded. “An obvious answer is tainted seafood. It can happen anywhere but there are precedents in that region.”

“Her travelling companion complained of milder but similar symptoms,” Sherlock said. “He refused treatment.”

“That’s a bit odd.”

“Also refused to have blood work done and did not provide a hair sample.”

“Seems... suspicious.”

“He claimed to be too jet lagged and sick at first, then grieving and insisted that he didn’t want to know if he was going to die horribly,” Sherlock added.

“And he’s being allowed to get away with this?” John asked. “I assume it was acute poisoning.”

“Extremely acute. The amounts of mercury in her system are frightening. If you read the accounts of her rapid degeneration, it’s pretty horrific.”

“I can imagine. So, how is Mycroft involved?”

Sherlock grimaced with distaste. “The victim is Lord Smallwood’s fifteen year old pregnant… I’ll use the word, _mistress_.” John’s eyes widened with shock. “It’s a repulsive situation but the family is saying nothing and he’s playing innocent rather well. There’s no evidence beyond the fact that she died and even death by mercury is not necessarily murder.”

“Especially with them travelling.”

“Exactly.”

“I’d say your boyfriend is involved.”

“Jim doesn’t usually sink that low,” Sherlock stated at the same time as his phone chimed with a text from Jim.

“Speaking of the devil,” John grumbled. “Let me look at this one more time while you deal with that.” Sherlock chuckled and then looked at his phone.

“What is the combination for the lock to Mycroft’s liquor cabinet? -JM

Pursing his lips, Sherlock shook his head and replied with a question of his own.

Do you know anything about mercury poisonings? -SH

It took Jim a few minutes to reply and Sherlock could only wonder what trouble his boyfriend was getting into at Mycroft’s mansion.

It’s a horrible way to go. -JM

You’re the second person of late, relatively speaking, to ask me that. -JM

That was intriguing. And worrisome. He didn’t want to imagine Jim being involved in _this_ case.

Do tell. I’m looking for evidence of murder. -SH

Victim? -JM

Jim’s question reassured him somewhat. If Jim wasn’t certain of the victim, then he couldn’t have been deeply involved. Jim didn’t lie to him.

Smallwood’s pregnant 15yo mistress. -SH

Nice. -.- -JM

Give me a minute. -JM

Sherlock sighed and went to retrieve the tea for himself and John. “Does he have anything?” John asked.

“By the questions that he was asking me, I suspect he’s not directly involved,” Sherlock answered. He handed John a mug of tea and sat down next to his friend. They sipped their tea in companionable silence until Sandra finished proofreading the new blog post. John published it and they made their excuses for the evening. Sherlock wasn’t unhappy to see them off. He began reviewing all the facts from the case. The sound of a text from Jim interrupted his musings.

“What is the combination for the lock to Mycroft’s liquor cabinet? -JM 

Sherlock stared at the message for a moment and decided that since Jim had repeated his question, he had something for Sherlock.

tyqkOihTt;cEHs5p8byG`eeDfZur/mWCrfCmfOBGF}zisNvsQdWr)RMxBf5faiF2  
fYksYTCwwbl7BiRwudSPcXA3Lp9w%um.-YePtSi4AjdpegfmGi~qqyHAxDUXyA*K -SH

He picks ridiculous passwords. -JM

I know. Not nearly as entertaining as IcemanSucksRainbowIceLollies245. -SH

Thanks! -JM

I’ll bring over his Rémy Martin cognac. -JM

He’ll kill you. -SH

¯\\_(ツ)_/¯ -JM

Sherlock shook his head but then another text came through. It was an image of a sales receipt. The CIA had sold one ten gram ampule of dimethylmercury to Charles Magnussen through Sigma-Aldritch. Magnussen had procured the toxin for Lord Smallwood; the two had historical business dealings.

Thank you. -SH

We’ll see you in a bit. -JM

Sherlock smiled while forwarding the image of the sales receipt to Mycroft.

We? -SH

The cognac and I! -JM

_The End_.


End file.
